Speed reducer

Abstract

A speed reducer has an input member, an output member provided coaxially with the input member and a cage disposed between opposite surfaces of the input member and the output member. The cage is formed with a plurality of pockets arranged circumferentially at equal intervals. A rolling element is received in each pocket. The output member is formed with recesses arranged circumferentially at equal intervals, the number of which is unequal to the number of the rolling elements. The input member is provided with a contact surface for pressing the rolling elements against the bottoms of the recesses when the input member rotates. In another arrangement, a cylindrical output member is provided around a disk-shaped input member. Disks are rotatably mounted in the input member and having part of their outer periphery protruding from the outer periphery of the input member. Each disk is provided along the outer periphery thereof with recesses arranged at intervals corresponding to the pitch of said rolling elements and engageable with the rolling elements.

What is claimed is: 
     
       1. A speed reducer comprising a disk-shaped input member having an outer peripheral surface, a cylindrical output member extending along the circumference of said input member and having an inner peripheral surface opposite the outer peripheral surface of said input member, a cage disposed between said input member and said output member, said cage being formed with a plurality of pockets arranged circumferentially at equal intervals between said peripheral surfaces of said input and output members, a plurality of rolling elements received in said respective pockets, said output member having a plurality of recesses in said inner peripheral surface thereof and said recesses being spaced circumferentially at equal intervals, the number of said recesses being different from the number of said rolling elements, and disks rotatably mounted in said input member and partially protruding radially from said outer peripheral surface of the input member, each said disk being provided along the outer periphery thereof with recesses arranged at intervals corresponding to the pitch of said rolling elements and engageable with said rolling elements.